Earthquakes and Tsunamis

A comprehensive vocabulary review of key terms, processes, and measurement tools related to earthquakes and tsunamis.

Tsunami

The Japanese word for an ocean wave, caused by an earthquake that occurs underwater; it gains energy and grows in height as it enters shallow water nearer the coastline.

Seismograph

A sensitive piece of technology that measures the strength of an earthquake by detecting vibrations in the ground and recording the data.

Seismologist

A person who studies earthquakes.

Earthquake

An intense shaking of the Earth's surface caused by plate movement.

Fault line

A crack in the Earth's crust where two plates meet, along which almost all earthquakes originate.

Sliding boundary

A plate boundary where two plates are locked together but still try to move, creating friction and built-up pressure over time that is released suddenly to cause powerful earthquakes.

Focus

The underground starting point of the earthquake where plate movement begins and where pressure is at its greatest.

Shockwaves

Vibrations that radiate outwards from the focus as plates move, carrying energy through the crust of the Earth and often reaching the surface.

Tremors

Smaller shockwaves that radiate outwards from plate movement.

Epicentre

The point on the surface of the Earth directly above the focus, where the most powerful effects of an earthquake are seen and the worst damage is done.

Aftershocks

Smaller shocks that can occur after the main earthquake and affect a large area, often causing further damage to already weakened buildings and injury to people.